This invention relates to a bearing assembly and more particularly to a new and novel bearing assembly for use in supporting a water lubricated propeller shaft as in large naval ships.
Bearing assemblies with elastomeric bearing elements are known to be particularly well suited for this purpose because of their excellent ability to withstand the effects of corrosive fluids and to abrasion resulting from particles of foreign matter carried in suspension in the sea water in which the shaft and bearing assembly operates.
One type of such bearing assembly includes an outer non-corrosive support or shell and a plurality of circumferentially evenly spaced elastomeric staves provided therein which support by selectively contacting the shaft.
Another type of such bearing assembly includes an outer non-corrosive support or shell and a larger elastomeric bearing contact surface provided therein which contacts the shaft over a larger circumferential area than the stave type bearing. This type of bearing is known as a round bore or partial arc bearing (in some cases).
Partial arc bearings are difficult to manufacture because of the exacting tolerances to which they must be made. Heretofore, partial arc bearings have been manufactured by attaching bearing members to the inner surface of the shell and machining the elastomer down to the proper dimension. The machining process, however, scars the elastomer, thereby significantly raising the coefficient of friction between bearing and shaft and the wear rate of both members.
Efforts to improve such bearings and their manufacture have led to continuing developments to improve versatility, practicality and efficiency.
An object of the invention is to provide a bearing slab for use in a bearing assembly used for supporting a water lubricated propeller shaft, having lower friction with the shaft than corresponding conventional bearing slabs.
Another object of the invention is to provide a bearing slab for use in partial arc bearing assembly for establishing low friction hydrodynamic bearing surfaces for a water lubricated propeller shaft rotating therein.
Still a further object is to provide bearing slabs for partial arc marine bearings for supporting water lubricated propeller shafts, the bearing slabs having an elastomeric bottom layer and a hard upper layer constructed to reduce friction with the shaft because of the creation of hydrodynamic bearing surfaces with the shaft.
The present invention provides a partial arc bearing having reduced coefficient of friction and wear rate while reducing manufacturing costs.
These and other objects, features and advantages of the present invention will become more apparent in the light of the detailed description of exemplary embodiments thereof, as illustrated by the drawings.